Jan 20, 2018 1730 UTC Day 2 Convective Outlook
Updated: Sat Jan 20 17:00:39 UTC 2018 (20180120 1730Z Day 2 shapefile | 20180120 1730Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20180120 1730 UTC Day 2 Outlook Graphic
Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 112,923 8,680,760 Dallas, TX...Plano, TX...Garland, TX...Shreveport, LA...Little Rock, AR...
Probabilistic Graphic
20180120 1730 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
Day 2 Prob. Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 112,424 8,866,493 Dallas, TX...Plano, TX...Garland, TX...Shreveport, LA...Little Rock, AR...
   SPC AC 201700

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1100 AM CST Sat Jan 20 2018

   Valid 211200Z - 221200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
   EAST TX INTO SOUTHWEST MO...

   ...SUMMARY...
   Isolated severe thunderstorms are possible Sunday afternoon and
   evening from east Texas into southwest Missouri. A SLGT risk may be
   warranted for portions of this region if instability is greater than
   currently expected.

   ...TX to MO...

   Latest short-range model guidance continues to suggest a strong
   southern-stream short-wave trough will eject across the southern
   Rockies to a position from western KS into west TX by 22/00z as an
   intensifying 500mb speed max translates into OK. In response to this
   feature, low-level trajectories will become increasingly favorable
   for modified moisture to advance inland across TX before advecting
   into the mid-MS Valley ahead of the short wave late in the period.
   However, moisture is expected to remain somewhat limited across the
   warm sector due to the disruptive influence of the short-wave trough
   that is currently ejecting across the northern Gulf Basin. As a
   result, a narrow wedge of 50s surface dew points are expected to
   return as far north as eastern OK/western AR into southwest MO prior
   to frontal passage Sunday evening, with lower 60s dew points
   primarily limited to east TX/southern AR/LA.

   As the trough shifts east it appears strong boundary-layer heating
   will develop across the southern High Plains into central OK during
   the afternoon and this should steepen surface-3km lapse rates along
   a pre-frontal corridor into eastern OK by 21z where values may
   approach 9 C/km. It appears surface-based convection will develop
   along a surging dry line over eastern OK/northeast TX between 21-00z
   and a strongly forced line of thunderstorms should mature along the
   wind shift by early evening. Forecast soundings across the MRGL risk
   region suggest near-surface based convection can be expected as far
   north as southwest MO. Given the strongest large-scale forcing for
   ascent will be maximized over the mid-MS Valley (240m 500mb height
   falls during the day) there is reason to believe an organized squall
   line will advance across eastern OK/northeast TX into AR/MO region
   after dark. Strong frontal forcing favors linear storm mode and
   damaging winds are the primary threat, especially as 500mb flow
   intensifies to near 100kt during the latter half of the period. Even
   so, a tornado or two can not be ruled out as forecast shear would
   support organized rotating updrafts. Have opted to maintain 5%
   severe probs given the relatively benign thermodynamic profiles, but
   a SLGT risk may be warranted if expected buoyancy improves.

   ..Darrow.. 01/20/2018

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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0700Z